It has been known for many years that food products have implications on the health of the consumer.
In particular, excessive consumption of fats in the human diet may cause the occurrence of serious pathologies notably generated by an increase in blood cholesterol and triglycerides, more specifically cholesterol.
In order to improve the health condition of the consumer, new low-fat products have been proposed, which unfortunately do not have the same organoleptic properties as the standard products.
The use of products defined as <<functional food>> has also been proposed which are made up from food products having a therapeutic or prophylactic effect within the scope of a supplement to the treatment and/or prevention of different pathologies (osteoporosis, cardiovascular diseases, cancer . . . ).
Such food ingredients for example consist of sugars, proteins, minerals or vitamins capable of improving or sustaining human health.
Document WO02/34062 describes a method for obtaining a product enriched in phospholipids and sphingolipids by ultrafiltration on a membrane having a cutoff value comprised between 5,000 and 20,000 Da and preferably depleted in or without any casein. In this document, with a concentration of sphingolipids (phospholipids, sphingomyelin) obtained by ultrafiltration of lactic buttermilk from butter factories, optionally deproteinized, or of a cheese industry/fresh cheese lactoserum, it is possible to obtain a milk ingredient enriched in polar lipids, in which the percentage of the phospholipids is less than 3% by weight relatively to the dry matter weight of the ingredient. This patent application also describes food products or food supplements comprising the product enriched in the obtained phospholipids and sphingolipids.
International patent application WO03/071875 describes a method for preparing from a cheese factory lactoserum, a concentrate enriched in milk polar lipids, in particular a concentrate enriched in milk sphingolipids from a cheese factory lactoserum. This device describes the use in parallel of ultrafiltration and diafiltration methods by means of 30,000 Da or 10,000 Da membranes. This method requires a preliminary proteolysis step (enzymatic hydrolysis of the proteins) of the raw material used (ultrafiltered cheese factory lactoserum). With this method, it is possible to obtain a concentrate enriched in sphingolipids (Ultra High Fat Concentrate—UHFC) which may then be treated with a phospholipase, in order to purify the obtained sphingolipids. However, the concentration of phospholipids in the obtained milk ingredient (by weight relatively to the dry matter weight of the ingredient), is less than 20%.
In addition, the obtained concentrated product will have deteriorated organoleptic properties due to the presence of peptide compounds originating from the proteolysis.
Furthermore, this document also describes a concentration method by ultrafiltration (in parallel), which is applied after enzymatic hydrolysis of the proteins. This enzymatic hydrolysis enables the protein fractions (peptides) to cross the ultrafiltration membrane and to be separated from the lipid fraction which remains retained by this membrane.
SACHDEVA et al. (in KIELER WIRTSCHAFTLICHE FORSCHUNGSBERICHTE VERLAG TH. MANN GELSENKIRCHEN, Volume 49 No. 1 1997 pp. 47-68) describe a method for recovering phospholipids from buttermilk by a chemical or physical treatment method. In this method, the raw material is sweetcream buttermilk powder which is submitted to a coagulation by adding rennet, citric acid or a lactic culture and calcium chloride, followed by a separation and a concentration of the serum through a membrane treatment by means of an ultrafiltration or a microfiltration. The obtained concentrate is a milk ingredient enriched in phospholipids in which the phospholipids percentage is less than 20% by weight relatively to the dry matter weight of the ingredient.
Japanese Application JP03/047192 describes a method of fractionation and purification of a phospholipids fraction derived from milk or from a dairy product, by using a centrifugal liquid-liquid partition (or sharing) chromatography step.
The extracts described in this patent application have purities greater than 80% or even 90%, but have been obtained by extractions with solvents (ether and acetone). The yields are unknown since the phospholipid concentration of the initial buttermilk is not given.
By applying centrifugal liquid-liquid partition chromatography in the presence of other solvents, the phospholipids may be separated and compounds purified at 97-98% are obtained, but the recovered amounts are less than one milligram (a laboratory technique).
Japanese Patent Application 2005 027 621 describes a method for purifying phospholipids from milk or from a dairy product by submitting these products to a microfiltration treatment by using membranes with a pore size comprised between 1 and 2 μm. With this method, it is possible to obtain a product having more than 30% by weight of phospholipids, optionally more than 35% by weight of phospholipids, this percentage being calculated on the basis of the dry matter of the composition (total dry extract). Furthermore, this document describes that, if the phospholipid concentration is greater than 35% by weight, it is possible to use the composition of the invention as an emulsifier.
This patent application describes a method for concentrating phospholipids by microfiltration of skimmed milk (defatted milk); a skimmed milk only contains the small fat globules alone, for which the <<surface/volume>> ratio is greater, which are therefore richer in phospholipids than the membrane lipids. The milk microfiltration method is traditionally used for removing the microorganisms. The obtained extract is washed and the phospholipid-enriched portion is recovered after breaking the emulsion. However, microfiltration of whole milk does not work, because it concentrates the fat in its integrality (no increase in the total phospholipid/fat ratio). Furthermore, by treating a very large amount of skimmed milk (which only contains 0.1% of fat) and from which only the agglomerates of fat globules, with a size larger than 2 μm, are recovered for obtaining small amounts of recovered phospholipids (20 metric tons of skimmed milk for recovering 200 g of a phospholipids-rich extract). Furthermore, the treatment also concentrates microbiological pollutants, which leads to mandatory washing, but this washing perhaps does not suppress all the risks.
The Japanese Patent Application JP2001 27 56 14 describes a composition containing phospholipids capable of having an advantageous action on the reduction of blood cholesterol and triglycerides, and an inhibiting action on the accumulation of neutral lipids in the liver. Additionally, a link between the disorders of the lipid metabolism and diabetes is also suggested in this document. Phospholipids used in this document are optionally obtained by known methods such as extraction by a solvent and the fractionation using different chromatographic means.
Aims of the Invention
The present invention is directed to obtain a milk ingredient enriched in lipidic components of the milk fat globule membrane, i.e. enriched in polar lipids, in particular in phospholipids and in sphingolipids and having particular physical properties but also and always including the characteristics of a milk ingredient, i.e. also substantially without any hydrolyzed proteins, while maintaining or improving typical organoleptic properties of a milk ingredient.
The present invention also aims to increase the organoleptic or structural properties of food compositions incorporating these ingredients and to provide an adequate daily dose of said polar lipids, in particular sphingolipids, so as to sustain or improve a satisfactory health condition of the consumer.
A particular aim of the present invention is to provide food compositions which allow the consumer to obtain a reduction in the blood cholesterol and triglyceride level, a preventive effect against cancer, in particular colon cancer, to reinforce immunity and intestinal flora of the consumer, to obtain antidiabetic effects (treatment and/or prevention of diabetes) and to ensure protection of the liver of the consumer.
A last aim of the invention is to propose a (physical) method for obtaining this milk ingredient which respects the organoleptic properties of the obtained milk ingredient and which is of simple and inexpensive conception and which has an improved yield in producing polar lipids, in particular phospholipids and sphingolipids which are particularly advantageous, which is expressed as a high weight percentage as compared with the dry matter percentage.
Characteristic Elements of the Invention
The present invention relates to a milk ingredient enriched in components of the milk fat globule membrane, i.e. enriched in polar lipids, in particular in phospholipids and in sphingolipids, but also depleted in proteins, in particular depleted in or without casein, while ensuring that the milk ingredient of the invention preserves the organoleptic properties of the dairy product from which it is derived.
By polar lipids, are meant lipids bearing a head or polar group at one of their ends. The most frequent polar lipids are phospholipids comprising phosphoric acid groups. Among these lipids, mention may be made of phosphoglycerides such as phosphatidylethanolamine, phosphatidylcholine, phosphatidylserine or phosphatidylinositol. The sphingolipids also include a polar head but no glycerol group.
Three subclasses of sphingolipids are distinguished: sphingomyelins, cerebrosides and gangliosides. Only sphingomyelins include a phosphoric acid group.
The sphingolipids mainly present in milk are sphingomyelin (SPH, or ceramide phosphorylcholine), ceramide glucosides, lactosyl ceramides and gangliosides.
The phospholipids mainly present are phosphatidylcholine (PC), phosphatidylethanolamine (PE), phosphatidylserine (PS) and phosphatidylinositol (PI). The other lipids present in the milk ingredient of the invention are neutral lipids (triglycerides) and cholesterol.
The proteins present in the product of the invention are milk proteins, i.e. mainly casein, lactalbumin and lactoglobulin.
The object of the invention relates to a milk ingredient enriched in these components from the membrane of the milk fat globules, in particular in polar lipids, i.e. a composition for which the concentration of these phospholipids, predominant components of polar lipids, is greater than 10% by weight, preferably greater than 20% by weight, preferably greater than 30% by weight, more particularly greater than 35%, 36%, 37%, 38% or 39% by weight, preferably about 39.4% by weight, calculated on the percentage of dry matter of the composition (total dry extract).
The other compounds present in the composition of the invention are water, proteins, carbohydrates, such as lactose, water-soluble vitamins, enzymes and ashes (minerals). In the subsequent text, lactose and ashes are also grouped together under the definition of non-protein defatted dry extract.
The milk ingredient of the invention is characterized by its high concentration of polar lipids, in particular phospholipids and of sphingolipids, as well as by its low relative concentration of its other milk components i.e., lactose, mineral salts but also proteins which are also preferably partly extracted during the polar lipid enrichment method.
Preferably, the product of the invention also comprises a low protein percentage, preferably less than 40%, more particularly less than 30%, preferably less than 28% (relatively to the dry matter content of the ingredient). Additionally, the composition also includes a certain percentage of saccharides (lactose), but which may also be extracted from the composition.
Advantageously, the proteins of the composition of the invention appear in a non-hydrolyzed form by the action of protease and/or peptidase enzymes, in order not to induce harmful effects on the organoleptic characteristics of the final obtained product (foodstuffs, pharmaceutical products, . . . ).
The milk ingredient of the invention may be present under solid form, preferably obtained by evaporation (thermal concentration and drying) of the water present in the composition of the invention, in order to obtain more stable products, more easy to handle and to dose, and less subject to biological denaturation.
Another aspect of the present invention relates to the method for obtaining the milk ingredient enriched in components from the milk fat globule membrane, and comprising particles (fat globules) of lipids having preferably a size less than 3 μm, comprised between about 1 μm and about 2.5 μm, in particular enriched in polar lipids, i.e. in phospholipids and in sphingolipids, preferably the milk ingredient of the invention. In particular, a milk ingredient enriched in polar lipids, i.e. a composition for which the concentration of phospholipids predominantly consisting of polar lipids, is greater than 10% by weight, preferably greater than 20% by weight, preferably greater than 30% by weight, or even greater than 35%, 36%, 37%, 38%, 39% by weight, preferably about 39.4% by weight, calculated on the dry matter percentage of the composition (total dry extract).
With the method of the invention, it is possible to obtain from a preferably pasteurized, milk cream, by combining different unitary operations, which are operations which do not alter the organoleptic properties of the obtained concentrated products and of the generated co-products, a milk ingredient enriched in these polar lipids, i.e. a composition for which the phospholipid concentration is greater than 10% by weight, preferably greater than 20% by weight, preferably greater than 30% by weight, greater than 35%, 36%, 37%, 38% or 39% by weight, preferably about 39.4% by weight, calculated on the dry matter percentage of the composition (total dry extract). This method comprises at least two successive and following steps of a treatment of a pasteurized milk cream:                concentration by centrifugation,        separation on a membrane (an ultrafiltration and/or ultrafiltration/diafiltration combination).        
Preferably, the method of the invention comprises at least one concentration step by centrifugation and a step of ultrafiltration/diafiltration of the composition increasingly enriched in polar lipids.
According to an alternative embodiment of the method of the invention, the latter comprises one or more steps of concentration by centrifugation and several ultrafiltration/diafiltration steps.
According to a preferred embodiment of the invention, the method of the invention further includes one or more steps of washing of the concentrated extracts, by adding pure (non-buffered) water, preferably before a new step of concentration by centrifugation.
Advantageously, the method of the invention also includes one or more (successive) so-called deproteinization steps and capable to very strongly reduce the concentration of the initially present proteins.
Preferably, this deproteinization (coagulation) step includes a thermo-calcium treatment for precipitating casein and separating the latter from the medium; the thermo-calcium treatment comprises the addition of about 0.1% of calcium chloride (w/w), followed by heat treatment at about 70° C. for about 40 minutes, adjustment of the pH to about 5.2 by adding a food acid (citric acid or lactic acid or phosphoric acid or hydrochloric acid); the subsequent separation of the precipitated proteins is performed by centrifugal decantation (by means of a separator of the solid phase from the liquid phase).
In the thermo-calcium treatment step of the invention, addition of citric acid is preferred, but this step for coagulating the proteins may also be obtained by action of rennet and of the acids mentioned above.
Preferably, in the method of the invention, the pasteurized milk cream is also submitted to a preliminary heat treatment, for example by a heating to a temperature comprised between about 60° C. and about 75° C., preferably to a temperature comprised between about 65° C. and about 70° C., for an adequate period of time (about 5 to about 20 minutes, i.e. the duration of the continuous centrifugation). The inventors unexpectedly observed that a particularly high phospholipids concentration in the milk ingredient is obtained by the method of the invention, as a result of the passage of the phospholipids into the serum. This effect is particularly significant in the examples illustrated below and is not obtained when soft buttermilk powder is used as a raw material, as described in the state of the art. Further, the inventors also observed that the use of certain acidifiers was particularly effective in the coagulation step, but unlike the state of the art, coagulation by adding suitable rennet for obtaining coagulation (deproteinization step) is not effective for forming intermediate products.
A last aspect of the present invention relates to a pharmaceutical composition (functional food), a cosmetic composition, a food composition or a food additive comprising (in addition to the adequate pharmaceutical or food carriers) the milk ingredient enriched in polar lipids, in particular in phospholipids and sphingolipids, according to the invention, in particular a milk ingredient enriched in polar lipids, i.e. a composition having a phospholipid concentration greater than 10% by weight, preferably greater than 20% by weight, preferably greater than 30% by weight, greater than 35% by weight, 36%, 37%, 38%, 39% or even about 39.4% by weight calculated on the dry matter percentage of the composition (total dry extract). Said food composition or said additive for a food composition present equivalent or improved organoleptic or structural properties compared to those of standard food products, prepared without this ingredient.
The pharmaceutical composition will comprise an adequate pharmaceutical carrier and said ingredient (as an active ingredient) in an adequate proportion in order to induce a therapeutic or preventive effect on certain pathologies (in particular those described in the examples).
The present invention will be described in more detail in the exemplary embodiments below, presented as non-limiting illustrations of the invention, with reference to the enclosed figures.